1. Field of the Invention
The invention relates to a heat pump type of multi-air conditioner (hereinafter, referred to as an air conditioner) suitable for simultaneously heating and cooling a plurality of rooms by using a single outdoor unit and two and more indoor units connected to the outdoor unit, and more particularly to an air conditioner control apparatus and method thereof which recognizes operation states of indoor units with communication between indoors units, and performs a normal operation of one indoor unit, even if the other indoor unit is under a safety operation mode (i.e., a defrosting operation, a high temperature operation, or a low temperature operation).
2. Description of the Prior Art
In general, there are provided two types of an air conditioner, i.e., one being a heating apparatus for heating cold air in a room and the other being a cooling apparatus for cooling warm air in the room.
There is also an apparatus having dual functions of heating and cooling the room, and in addition an air-cleaning function for cleaning polluted indoor air.
Referring to FIG. 1, there is illustrated a conventional air conditioner of a cooling-only apparatus.
As shown in FIG. 1, when refrigerant compressed by a compressor 1 to gaseous state at high temperature and high pressure is infused to an outdoor heat exchanger 2, the outdoor heat exchanger 2 serves to heat-exchange the same with air blown by an outdoor fan (not shown), and forcibly cool the refrigerant to allow the same to be liquefied.
The fluid refrigerant of low temperature and high pressure liquefied at the outdoor heat exchanger 2 passes through an expansion valve 3 for expanding the refrigerant to an evaporating pressure, reduced in pressure to become atomized refrigerant of low pressure and low temperature and is infused to an indoor heat exchanger 4.
Accordingly, the atomized refrigerant reduced to low pressure and low temperature at the expansion valve 3 is evaporated in the course of passing through various pipes and takes heat from the air blown by an indoor fan 9 in the course of being gasified, to thereby cool the air in a room.
The cooled air (blown) is in turn discharged indoors to thereby perform a cooling operation. The gaseous refrigerant of low pressure and low temperature cooled at the indoor heat exchanger 4 is in turn fed to the compressor 1 and circulated repeatedly through a cooling loop as illustrated by continuous solid line arrows in FIG. 1.
However, there is a problem in the conventional air conditioner for performing the cooling operation according to the cooling cycle thus described, in that various rooms cannot be simultaneously cooled because of the individual cooling operation performed by one outdoor unit for controlling one indoor unit, and an indoor heating cannot be performed.
By way of another prior art of utilizing an invert air conditioner for performing dual operations of cooling and heating the room (see FIG. 2), when refrigerant compressed in gaseous state of high temperature and high pressure at the compressor is infused into the outdoor heat exchanger 2 according to control of a four-way valve 5, as shown in FIG. 2, the outdoor-heat exchanger 2 serves to forcibly cool the gaseous refrigerant compressed in high temperature and high pressure by way of the air blown by the outdoor fan, thereby liquefying the same.
The fluid refrigerant of low temperature and high pressure liquefied by the outdoor heat exchanger 2 passes through the expansion valve 3 for expanding the same to evaporative pressure via an one way valve 7 to thereby be reduced to atomized refrigerant of low pressure and low temperature and to be infused into the indoor heat exchanger 4.
Accordingly, the atomized refrigerant in the indoor heat exchanger 4 reduced to low temperature and low pressure at the expansion valve 3 takes the heat from the air blown by the indoor fan 9 to thereby cool the air in the room when the atomized refrigerant passes through various pipes and is evaporized and is finally gasified. The cooled air (blown) is in turn discharged indoors to thereby perform a cooling operation. The gasified refrigerant of low pressure and low temperature cooled by the indoor heat exchanger 4 is in turn fed into the compressor 1 and circulates repeatedly through a cooling loop as illustrated by solid line arrows in FIG. 2, thereby performing the indoor cooling operation.
Meanwhile, in case of heating, when the refrigerant compressed to gaseous state of high pressure and high temperature by the compressor 1 is infused into the indoor heat exchanger 4 according to the control of the four-way valve 5, the indoor heat exchanger 4 serves to heat-exchange the air blown by the indoor fan 9, to thereby cool the refrigerant to room temperature and high pressure. Thus, the heated air is discharged to perform the heating operation.
The refrigerant liquefied by the indoor heat exchanger 4 is reduced to refrigerant of low temperature and low pressure by the expansion valve 3 and an expansion valve 6 and is then infused into the outdoor heat exchanger 2.
Accordingly, the outdoor heat exchanger 2 serves to heat-exchange the refrigerant reduced in pressure at the expansion valve 3 and the expansion valve 6 by way of the air blown by the outdoor fan 8, thereby cooling the refrigerant.
The gasified refrigerant of low temperature and low pressure cooled by the outdoor heat exchanger 2 is in turn fed into the compressor 1 and circulated repeatedly through a heating loop as illustrated by dotted line arrows in FIG. 2, thereby performing an indoor heating operation.
However, there is a problem in the air conditioner depicted in FIG. 2 in that heating cannot be performed during the cooling operation and cooling cannot be performed during the heating operation, thereby making it impossible to cater to various demands by consumers and to simultaneously perform the heating and the cooling operations, although there is an advantageous point in that the heating and the cooling can be executed by one outdoor unit controlling one indoor unit.
To overcome those problems, the present applicant has proposed another type of an air conditioner capable of simultaneously cooling and heating various room spaces by using two and more indoor units connected to a single outdoor unit, this unit having two compressors and two four-way valves. However, one indoor unit cannot know the operation states of the other indoor units due to the absence of communications between various indoor units. In case the safety operation mode (defrosting, high or temperature operations of the air conditioner) in one indoor unit is performed, the operation of other indoor unit has to be forcibly stopped, in order to perform an air conditioner control.